selfupdate and readline support

[Ryan Schmidt]

On Jan 12, 2009, at 19:01, Blair Zajac wrote:

> Rainer Müller wrote:
>> Joshua Root wrote:
>>> This thread is what led to readline being disabled by default:
>>> <http://lists.macosforge.org/pipermail/macports-users/2007- 
>>> November/006973.html>
>> So anyone who wants readline support should just install from the  
>> disk
>> images? I think most people do not use the interactive port shell  
>> at all
>> and do not need readline, therefore this should be a reasonable  
>> decision.
>> Thanks for digging in the archives for me ;-)

I think it's wrong that we ship binaries that enable readline, and  
then a selfupdate disables readline again. The selfupdate should keep  
the readline support enabled. Thanks for pointing out this problem.

> You can always wrap the interactive command with rlwrap or ledit to  
> get history and in-line editing also.

That's a workaround only, not a solution.

To summarize the November 2007 thread, the --enable-readline switch  
to MacPorts' configure script can cause the build to fail with a  
weird error if the user has installed another version of readline in  
the prefix /usr/local. In that particular case, the user had a  
PowerPC version of readline on their Intel Mac that had been migrated  
there from an older Mac by Apple's Migration Assistant. The user may  
not know or remember that they installed readline there. Because  
similar issues were affecting other users, readline was disabled by  
default.

I said then [1], and still say now, that we need a more general  
solution that makes MacPorts display a warning to the user if they  
install software in the prefix /usr/local. We have never supported  
the user installing software in the prefix /usr/local [2] and it  
causes problems in many more situations than this. MacPorts should  
actively inform users that they are doing things they should not, and  
how to correct them (even if that's only by providing a link to a FAQ  
entry or Guide section).

[1] http://lists.macosforge.org/pipermail/macports-users/2007- 
November/006982.html

[2] http://trac.macports.org/ticket/15077